On 09/21/2017 09:45 AM, Maged Mokhtar wrote: > On 2017-09-21 07:56, Lazuardi Nasution wrote: > >> Hi, >> >> I'm still looking for the answer of these questions. Maybe someone can >> share their thought on these. Any comment will be helpful too. >> >> Best regards, >> >> On Sat, Sep 16, 2017 at 1:39 AM, Lazuardi Nasution >> <mrxlazuardin@xxxxxxxxx <mailto:mrxlazuardin@xxxxxxxxx>> wrote: >> >> Hi, >> >> 1. Is it possible configure use osd_data not as small partition on >> OSD but a folder (ex. on root disk)? If yes, how to do that with >> ceph-disk and any pros/cons of doing that? >> 2. Is WAL & DB size calculated based on OSD size or expected >> throughput like on journal device of filestore? If no, what is the >> default value and pro/cons of adjusting that? >> 3. Is partition alignment matter on Bluestore, including WAL & DB >> if using separate device for them? >> >> Best regards, >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx <mailto:ceph-users@xxxxxxxxxxxxxx> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > I am also looking for recommendations on wal/db partition sizes. Some hints: > > ceph-disk defaults used in case it does not find > bluestore_block_wal_size or bluestore_block_db_size in config file: > > wal = 512MB > > db = if bluestore_block_size (data size) is in config file it uses 1/100 > of it else it uses 1G. > > There is also a presentation by Sage back in March, see page 16: > > https://www.slideshare.net/sageweil1/bluestore-a-new-storage-backend-for-ceph-one-year-in > > wal: 512 MB > > db: "a few" GB > > the wal size is probably not debatable, it will be like a journal for > small block sizes which are constrained by iops hence 512 MB is more > than enough. Probably we will see more on the db size in the future. This is what I understood so far. I wonder if it makes sense to set the db size as big as possible and divide entire db device is by the number of OSDs it will serve. E.g. 10 OSDs / 1 NVME (800GB) (800GB - 10x1GB wal ) / 10 = ~79Gb db size per OSD Is this smart/stupid? Dietmar -- _________________________________________ D i e t m a r R i e d e r, Mag.Dr. Innsbruck Medical University Biocenter - Division for Bioinformatics Innrain 80, 6020 Innsbruck Phone: +43 512 9003 71402 Fax: +43 512 9003 73100 Email: dietmar.rieder@xxxxxxxxxxx Web: http://www.icbi.at
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